Man 2002, pp. 166–67:"The half-folio page (30.7 x 44.5 cm) was made up of two rectangles—the whole page and its type area—based on the so called 'golden section', which specifies a crucial relationship between short and long sides, and produces an irrational number, as pi is, but is a ratio of about 5:8 (footnote: The ratio is 0.618.... ad inf commonly rounded to 0.625)" Man, John (2002). Gutenberg: How One Man Remade the World with Words. Wiley. ISBN978-0-471-21823-4.
Tschichold 1991, p. 43, Fig 4: "Framework of ideal proportions in a medieval manuscript without multiple columns. Determined by Jan Tschichold 1953. Page proportion 2:3, margin proportions 1:1:2:3, type area proportioned in the Golden Section. The lower outer corner of the type area is fixed by a diagonal as well." (in the Dutch version, "letterveld volgens de Gulden Snede"—type area in accord with the Golden Section Tschichold, Jan (1991). The Form of the Book: Essays on the Morality of Good Design. Hartley & Marks. ISBN978-0-88179-116-7.
Egger 2004, p. 52. Egger, Willi (2004). "Help! The Typesetting Area"(PDF). Maps. 30. De Nederlandstalige TeX Gebruikersgroep. shows the Van de Graaf canon and a variant that divides the page into twelfths)